What to do in case of ora-12543: tns:destination host unreachable?

2.9K Asked by DonnaChapman in SQL Server , Asked on Feb 7, 2023

I have a installed oracle 19c

but i am unable to login

What must I do?

If you see the ora-12543: tns:destination host unreachable, you should follow the below steps:

1) we have to login to the sqlplus in the command prompt and connect as sysdba

sql>connect /as sysdba;2 ) alter the sys and unlock the account.

ALTER USER sys IDENTIFIED BY [newpassword] ACCOUNT UNLOCK;

  3 ) you can login via following url :https://localhost:5500/em

  4 ) Enter the username as sys and new newpassword<br>

5 ) you can able login as sys account and continue with your dba works

Your Answer

Answer (1)

Ranjana

The ORA-12543 error typically occurs when the Oracle client cannot connect to the Oracle server because the specified destination host is unreachable. Here are some steps you can take to troubleshoot and resolve this issue:

Check Network Connectivity: Ensure that the network connection between the client and the server is working properly. Ping the server from the client machine to verify connectivity.

Verify Hostname and Port: Double-check that the hostname and port specified in the connection string are correct. Ensure there are no typos or errors in the configuration.

Firewall Configuration: Make sure that the firewall settings on both the client and server machines allow communication over the specified port. If necessary, adjust the firewall rules to permit Oracle traffic.

Check Listener Status: Verify that the Oracle Listener service is running on the server. You can do this by using the lsnrctl status command on the server machine.

Verify Listener Configuration: Ensure that the listener configuration (listener.ora) on the server is correct and includes the appropriate entry for the database instance you are trying to connect to.

Restart Services: Sometimes, simply restarting the Oracle services on the server or the client machine can resolve connectivity issues. Restart the Oracle Listener service (lsnrctl stop followed by lsnrctl start) and try connecting again.

Check Server Availability: Make sure that the Oracle database server is up and running. If the server is down or undergoing maintenance, you won't be able to establish a connection.

Review Log Files: Check the Oracle alert log and listener log files for any errors or warnings that might provide clues about the cause of the connectivity issue.

Consult Documentation: If you're still unable to resolve the issue, consult the Oracle documentation or seek assistance from your database administrator or IT support team for further troubleshooting.

By following these steps, you should be able to diagnose and resolve the ORA-12543 error and establish a successful connection to the Oracle database.

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